Hangfire combines the optical technology of spherical lenses, mimicking the eye 's shape to minimize distortion, with Zeal 's award winning Observation Deck Technology (ODT) pantoscopic-tilt design, allowing you to see 20% more of the slope below you with zero distortion. With its sleek rimless design, incredible peripheral field of view and helmet compatibility, Hangfire takes a minimalistic approach to revolutionizing the way you see winter. Zeal Hangfire Goggles + Alchemy Mirror Lens | Black | Christy Sports